pmahoney

Orien is correct, it is the fork() system call triggered by ProcessBuilder or Runtime.exec or other means of the JVM executing an external process (e.g. another JVM running ant, a git command, etc.).

There have been some posts on the Jenkins mailing lists about this: Cannot run program "git" ... error=12, Cannot allocate memory

There is a nice description of the issue on the SCons dev list: fork()+exec() vs posix_spawn()

There is a long standing JVM bug report with solutions: Use posix_spawn, not fork, on S10 to avoid swap exhaustion. But I'm not sure if this actually made it into JDK7 as the comments suggest was the plan.

In summary, on Unix-like systems, when one process (e.g. the JVM) needs to launch another process (e.g. git) a system call is made to

pmahoney

require 'jruby/core_ext'

class MyObserver
  include Java::JavaUtil::Observer

  def update(observable, arg)
    puts "UPDATE! #{observable}"
  end
end
MyObserver.become_java! false

pmahoney

FROM busybox:1.31.0
ENTRYPOINT ["echo", "it worked"]

pmahoney

require 'java'

class Task
  include Java::JavaUtilConcurrent::Callable

  def initialize(num)
    @num = num
  end

  def call

pmahoney

require 'bundler'

# First attempt a bundle install without remote resolution.  In the
# happy case, all gems are already installed, and checking this is
# quick.  If it fails, attempt a remote resolution.  This is slow
# (probably largely because of how many dang gem versions we have in
# our local gem server), but it will install anything that is missing.
#
# Bundler uses lots of class-level configuration, and thus isn't
# designed to be called repeatedly with different options, but we're

pmahoney

require 'benchmark'

A = 'a'
B = 'b'
C = 'c'
D = 'd'
E = 'e'
F = 'f'
G = 'g'
H = 'h'

pmahoney

See https://github.com/pmahoney/assets_comp_perf

rails 3.2.9, hike 1.2.1, sprockets 2.2.2

* denotes best time

Ruby 1.9.3-p194

    $ time bundle exec rake assets:clean assets:precompile

pmahoney

Rails 3.1.8 app in Ruby 1.8 compatibility mode with ~65 dependencies
(not sure how many in total including
transient deps) was timed up to the Bundler.require line in config/application.rb
(JRuby 1.7.0)

Before: 18.8 seconds
After:  15.9 seconds

This likely seriously breaks the semantics of 'require', and maybe isn't faster
enough to be worth it.

pmahoney

this	SunJCE_y  (id=144)	
arg0	true	
arg1	"DESede/CBC/PKCS5Padding" (id=249)	
arg2	 (id=254)	

pmahoney

public class Time {
    
    private final long timeInMillis;
    
    private final long nsec;
    
    public Time(long timeInMillis, long nsec) {
        this.timeInMillis = timeInMillis;
        this.nsec = nsec;
    }